The Battle of Cold Harbor was fought during the American Civil War near Mechanicsville, Virginia, from May 31 to June 12, 1864, with the most significant fighting occurring on June 3. It was one of the final battles of Union Lt. Gen. Ulysses S. Grant's Overland Campaign. Thousands of Union soldiers were killed or wounded in the frontal assault of June 3 against the fortified positions of Confederate Gen. Robert E. Lee's army—an action that intensified criticism of Grant's perceived indifference to heavy casualties.